Process of modifying the ash resulting from the combustion of powdered fuel.



W. P. BARBA.

PROCESS OF MODIFYING THE ASH RESULTING FROM THE COMBUSTION 0F POWDERED FUEL. APF'LICAHON FILED AUGJ], 19H.

1,167A7Q. Patented Jan. 11, 1916.

J M70171 P502360 lUNT @A% ATENT. @FFTGE WILLIAM P. BARBA, 0F PHILADELPHIA, PENNSYLVANIA, AS SIGNOR TO THE MIDVALE STEEL COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENN- SYLVANIA.

PROCESS OF MODIFYING THE ASH RESULTING FROM COMBUSTION OF POWDERED FUEL.

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Specification of Letters Patent.

Patented Jan. llll, 11916.

Application filed August 17, 1914. Serial No.- 857,108.

To all whom it may concern:

Be it known that 1, WILLIAM P. BARBA, a citizen of the United States, residing at Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented a new and useful Improvement in Processes of Modifying the Ash Resulting from the Combustion of Powdered Fuel, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part of this specifi cation.

My invention relates to the process of burning powdered coal in a furnace containing billets or other articles of metal to be heat-treated or to be heated preparatory to forging. The known advantage of this process is that it supplies heat at a relatively low price. The process of course involves the deposition of the ash upon the walls of the furnace and the articles undergoing treatment, which has certain advantages so far as concerns the said articles in that it affords a coating that acts to reduce oxidation.- The process, however, has certain deleterious effects, particularly upon the articles undergoing treatment. While the coating of the articles with ash tends to reduce oxidation, the ash usually fails to fuse with the scale to such an extent as to form a perfectly satisfactory protective coating, which scale is not only therefore so great in depth as to involve a considerable loss of metal, but often adheres so closely to the articles as to render its removal, necessary prearatory to forging, somewhat difficult. lhe process also has deleterious effects upon the furnace walls, arising from the deposit of fused ash, which reacts chemically and physically by lowering the melting point of the materials of which the furnace is composed and causing them to flux away and break down; and further, the continuous deposit and adhesion of the ash builds up the walls to an extent involving a serious reduction in the capacity and efliciency of the furnace.

My invention consists in adding to the coal an inorganic acid substance, preferably silicon dioxid, in quantity in excess of that required to bind the excess of alkalis contained in the coal and afford a sufficient amount of free acid to combine with the the Weight of the ash or more than twoper cent. of the weight of the coal, especially where the furnace lining is of an acid character and the particular fuel employed contains impurities in which basic substances predominate. The addition of this proportion of inorganic substance of an acid character raises the melting point of the ash to such an extent as to avoid the reaction chemically and physically, of the ash upon the furnace walls. The invention, however,

in its broader scope, is not limited to the use of the preferred proportions of an inorganic acid substance, as the use of such material in the proportion of from ten to twenty per cent. of the weight of the ash will afford a sufficient amount of free acid to combine with the scale and limit the thickness thereof and hence minimize the loss of metal and also avoid adhesion of the scale to the unoxidized body of the billet, even though the addition is not sufficient to raise the melting point of the ash; but if the addition is sufficient to substantially raise the melting point of the ash, the metal articles will be equally effectively protected with the additional advantage that the action of the ash upon the furnace'wall will be overcome. If the preferred larger quantity of the inorganic acid substance be added, the process will be applicable to the use of powdered coal for heating metals in a fluid state, as in an open hearth furnace.

In order that the process to which my invention may be applied may be fully understood, I have illustrated an apparatus, the single figure of which is a' transverse sectional view of a furnace arranged for the burning of powdered fuel mixed with an inorganic. acid substance as above described.-

a is the hearth of the furnace and Z the combustion chamber separated therefrom by a baffle 0.

(Z is a pipe of large capacity through which air is introduced at a relatively low pressure to the combustion chamber of the furnace.

e is a pipe leading from a hopper 9 containing powdered fuel which is fed from the hopper in regulated quantities by the feed rollers it. The pipe 6 extends into and is arranged concentrically within the pipe d.

f is a pipe through which air at a relatively high pressure is admitted into the pipe 6 in such a way as to force the fuel through the pipe e, at the outlet of which it mixes with the air admitted fromthe pipe 0? and ignites in the combustion chamber; the

battle a acting to spread and distribute the burning fuel throughout the space above the hearth a.

2', i, are billets undergoing treatment.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. The process of modifying the ash produced in burning powdered coal in a furnace containing metal articles to be heat treated, which consists in adding to the powdered coal an inorganic acid substance in quantity substantially in excess of that required to bind the excess of alkalis contained in the coal and sufiicient to afford a substantial amount of free acid to combine with the scale and form a protective coating against further oxidation.

2. 'ihe process of modifying the ash produced in burning powdered coal in a furnace which COIISIStS in adding to the powdered coal an inorganic acid substance in quantity substantially in excess of that required to bind the excess of alkalis contained in the coal and sufiicient to substantially raise the melting point of the ash.

3. lhe process of modifying the ash produced in burning powdered coal in a furnace which consists in adding to the powdered coal an inorganic acid substance in an amount in excess of twentv per cent. of the ash-formlng constituents of the coal.

In testimony of which invention, I have hereunto set my hand, at Philadelphia, on this 27th day of July, 1914.

JOSEPH ENTWISLE, ARTHUR KRONEMANN. 

